The present invention generally relates to a visual display. More particularly, the present invention relates to a liquid crystal display having enhanced viewing angle characteristics which is substantially free from a conventional color shift phenomenon.
In many applications, liquid crystal displays ("LCDs") have replaced cathode ray tubes, which are commonly known as "CRTs," for a variety of reasons. In particular, LCDs are much thinner and generally lighter in weight than conventional CRTs. Other applications using LCDs are desiring a variety of features such as making the panel size larger, enhancing contrast ratio, widening viewing angle, and reducing response time.
A common type of conventional technology used in these displays is called conventional twisted nematic ("TN") display mode. TN mode LCDs have been widely used since they have high definition of black and white colors, and rapid response time. In such a TN mode LCD, pixel electrode and counter electrode are respectively arranged on inner surfaces of two transparent substrates opposite each other. A liquid crystal layer including a plurality of liquid crystal molecules is generally sandwiched between the inner surfaces of the two substrates. The liquid crystal molecules generally maintain a "twisted state" on an absence of a voltage applied to the two electrodes, while they are aligned normal to the surface of the substrates as a voltage higher than a critical voltage is applied. Conventional TN mode LCDs, however, have intrinsic properties of narrow viewing angle and slow response time for gray scale operation.
In order to solve some of these limitations, various techniques have been used or suggested. As merely an example, an in-plane switching ("IPS") mode technique, where pixel and counter electrodes are arranged on the same substrate, has been proposed. The displays with IPS mode have a wider viewing angle to some degree, but still have a narrower viewing angle in a direction normal to the electric field direction that is produced between the pixel and counter electrodes. Moreover, the displays often have color shift caused by a structural property of liquid crystal molecules having longer and short axes. Accordingly, conventional LCDs have numerous limitations.
From the above, it is seen that a technique including a method and device for improving LCDs is highly desired.